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Abstract:

A vehicle signal light assembly includes: at least one color mixing light
source; a support element configured to support the at least one color
mixing light source on a vehicle as a signal light; and a controller
configured to selectively drive each color mixing light source to
generate light of a selected visually perceived color based on a received
control signal. In some such embodiments, each color mixing light source
of the vehicle signal light assembly comprises a plurality of light
emitting diodes (LEDs) of at least two constituent colors. In some such
embodiments, the controller is configured to operate each color mixing
light source of the vehicle signal light assembly using time domain
multiplexing (TDM) to generate the light of the selected visually
perceived color. In some such embodiments, the vehicle signal light
assembly comprises a taillight assembly. In some of the embodiments, the
vehicle light assembly comprises an ambient or auxiliary lighting, or a
dashboard lighting assembly.

Claims:

1. An apparatus comprising: a vehicle signal light assembly including: at
least one color mixing light source; a support element configured to
support the at least one color mixing light source on a vehicle as a
signal light; and a controller configured to selectively drive each color
mixing light source to generate light of a selected visually perceived
color based on a received control signal.

2. The apparatus as set forth in claim 1, wherein each color mixing light
source of the vehicle signal light assembly comprises a plurality of
light emitting diodes (LEDs) of at least two constituent colors.

3. The apparatus as set forth in claim 1, wherein the controller is
configured to operate each color mixing light source of the vehicle
signal light assembly using time-domain multiplexing (TDM) to generate
the light of the selected visually perceived color.

4. The apparatus as set forth in claim 1, wherein the vehicle signal
light assembly includes a plurality of color mixing light sources and
further includes: a single piece transparent or translucent cover
disposed over all the color mixing light sources.

5. The apparatus as set forth in claim 1, wherein the vehicle signal
light assembly further includes: at least one additional light source
that is not a color mixing light source; wherein the controller is
further configured to cause the at least one additional light source to
generate light responsive to a received control signal.

6. The apparatus as set forth in claim 1, wherein the controller is
configured to drive the at least one color mixing light source of the
vehicle signal light assembly to emit visually perceived white light
responsive to a backup signal.

7. The apparatus as set forth in claim 6, wherein the controller is
further configured to drive at least one color mixing light source of the
vehicle signal light assembly to emit visually perceived red light
responsive to at least one of a taillight or brake signal.

8. The apparatus as set forth in claim 7, wherein the controller is
further configured to drive at least one color mixing light source of the
vehicle signal light assembly to emit visually perceived yellow light
responsive to a turn signal.

9. The apparatus as set forth in claim 6, wherein the controller is
further configured to drive at least one color mixing light source of the
vehicle signal light assembly to emit visually perceived yellow light
responsive to a turn signal.

10. The apparatus as set forth in claim 1, wherein the controller is
configured to drive at least one color mixing light source of the vehicle
signal light assembly to emit (i) visually perceived red light responsive
to at least one of a taillight or brake signal and (ii) visually
perceived yellow or amber light responsive to a turn signal.

11. The apparatus as set forth in claim 1, wherein the controller is
configured to drive at least one color mixing light source of the vehicle
signal light assembly to emit visually perceived red light with a color
point adjustment selected by an adjustment input.

12. The apparatus as set forth in claim 11, further comprising: an
environmental sensor generating the adjustment input.

13. The apparatus as set forth in claim 12, wherein the environmental
sensor is selected from the group consisting of: a precipitation sensor,
a humidity sensor, a visibility sensor, an altitude sensor, and an
ambient light sensor.

14. The apparatus as set forth in claim 1, wherein the controller drives
each color mixing light source of the vehicle signal light assembly to
generate light of the selected visually perceived color using one of (i)
a constant d.c. current and (ii) a constant root-mean-square (rms) a.c.
current.

15. The apparatus as set forth in claim 1, wherein the controller is
configured to drive at least one color mixing light source of the vehicle
signal light assembly to alternate between a visually perceived first
color light and a visually perceived second color light different from
the visually perceived first color light responsive to simultaneous first
and second control signals respectively selecting the visually perceived
first color light and the visually perceived second color light.

16. The apparatus as set forth in claim 1, wherein the controller is
configured to selectively drive at least one color mixing light source of
the vehicle signal light assembly to generate light of a selected
visually perceived color with a color point adjusted based on a color
point adjustment parameter.

17. The apparatus as set forth in claim 16, wherein the color point
adjustment parameter is defined by a configuration setting of the
controller.

18. The apparatus as set forth in claim 17, wherein the configuration
setting of the controller selects a geographical region.

19. The apparatus as set forth in claim 16, wherein the color point
adjustment parameter is defined by an environmental measurement signal
received by the controller.

20. The apparatus as set forth in claim 1, wherein the visually perceived
color selected based on a received control signal is further selected
based on a configuration setting stored in the vehicle signal light
assembly.

21. The apparatus as set forth in claim 20, wherein the configuration
setting has first and second values and the visually perceived color
selected based on a received turn signal is red if the configuration
setting has the first value and yellow if the configuration setting has
the second value.

22. The apparatus as set forth in claim 20, wherein the configuration
setting is stored in the vehicle signal light assembly as one of (i) a
mechanical switch setting and (ii) data stored in an electronic
configuration memory.

23. The apparatus as set forth in claim 1, wherein the vehicle signal
light assembly comprises a taillight assembly.

24. The apparatus as set forth in claim 1, further comprising: a vehicle;
wherein the vehicle signal light assembly is supported by the support
element on the vehicle and the controller is operatively connected with
the vehicle to operate the vehicle signal light assembly based on a
control signal received from the vehicle.

25. The apparatus as set forth in claim 1, wherein the at least one color
mixing light source includes: a color mixing light source array module;
and an optical module comprising a plurality of optical paths each
coupled with one or more light source elements of the color mixing light
source array module, the optical paths comprising passive optical
elements.

26. The apparatus as set forth in claim 1, wherein the controller is
further configured to selectively drive at least two of the color mixing
light sources to generate light of the same selected visually perceived
color based on a received control signal.

27. A method comprising: generating a vehicle signal emanating from a
vehicle by: emitting signaling light of a first visually perceived color
responsive to a first control signal using a color mixing light source
mounted on the vehicle, the signaling light of the first visually
perceived color comprising a mixture of light of at least two different
constituent colors; and emitting signaling light of a second visually
perceived color responsive to a second control signal using the color
mixing light source mounted on the vehicle, the second visually perceived
color being different from the first visually perceived color.

28. The vehicle signal method as set forth in claim 27, wherein the
emitting signaling light of the first visually perceived color comprises:
emitting signaling light of the first visually perceived color by
time-domain multiplexing (TDM) mixing of light of at least two different
constituent colors.

29. An apparatus comprising: a taillight assembly configured to be
mounted on and operatively connected with a vehicle, the taillight
including: a color mixing light source, and a controller configured to
drive the color mixing light source to generate light of a selected one
of at least two different selectable visually perceived colors based on a
control signal received by the taillight assembly from the vehicle.

30. The apparatus as set forth in claim 29, wherein the controller is
configured to drive the color mixing light source to generate light of a
selected one of at least two different selectable visually perceived
colors using time-domain multiplexing (TDM) mixing of light of at least
two different constituent colors.

31. A system comprising: a plurality of vehicle optical modules wherein
each vehicle optical module includes a plurality of optical paths
comprising passive optical elements; and a color mixing light source
array module comprising a plurality of light source elements and an
electronic controller, the color mixing light source array module being
interchangeably optically coupleable with any one vehicle optical module
of the plurality of vehicle optical modules to inject light into the
optical paths of the coupled vehicle optical module, the electronic
controller operating the light source elements to emit light of selected
visually perceived colors into the optical paths of the coupled vehicle
optical module.

32. The system of claim 31, wherein the plurality of vehicle optical
modules include taillight optical modules for different vehicle
make/models.

33. The system of claim 31, wherein the plurality of vehicle optical
modules include at least (1) a taillight optical module and (2) a vehicle
interior lighting optical module.

34. An apparatus comprising: a vehicle ambient or auxiliary light
assembly including: at least one color mixing light source; a support
element configured to support the at least one color mixing light source
on a vehicle as a signal light; and a controller configured to
selectively drive each color mixing light source to generate light of a
selected visually perceived color based on a received control signal.

Description:

BACKGROUND

[0001] The following relates to the illumination arts, lighting arts, and
related arts.

[0002] Automotive indicator lighting must conform with applicable
regulatory- and safety-related constraints, while also remaining
cost-effective. In the highly competitive automotive market, a savings of
a small fraction of a dollar per unit can translate into substantial cost
savings. Additionally, automotive indicator lighting is an integral part
of the overall design of the automobile, and accordingly should have an
appealing appearance.

[0003] In the United States, automotive indicator lighting includes left
and right taillight assemblies, as well as various optional or mandatory
side and front signal light assemblies. Each taillight assembly includes
a taillight that illuminates in red whenever the automobile headlights
are on to enhance rear visibility of the vehicle. Each taillight assembly
also includes a brake light that illuminates a brighter red (as compared
with the taillight) to indicate application of the brakes, so as to warn
following drivers of the vehicle braking operation. The brake light can
be implemented either as a separate light or multi-filament assembly, or
can be the same as the taillight but operated at a higher intensity.
Still further, each taillight assembly includes a backup light, which
must be white. Finally, each taillight assembly must include a turn
signal light, which can be either red or yellow, but in either case must
flash on and off. The basic requirements in Europe are similar, except
that in Europe yellow turn indicator lights are mandatory.

[0004] The various signal components of the taillight assembly must be
independently operable in order to simultaneously inform other road users
of simultaneous vehicle conditions or events. For example, it may be that
the automobile is backing up while simultaneously braking and turning. In
such a case, the brake light must be on, the turn indicator light must be
on, and the white backup light must be on, all simultaneously.
Accordingly, the taillight assembly typically includes either three
lights (in designs utilizing a combined taillight/brake light) or four
lights (in designs utilizing a separate taillight and brake light).

[0005] The "red", "white", and "yellow" (sometimes also referred to as
"amber") colors are typically constrained by applicable regional
regulations that specify more precisely the shade or hue or equivalent
information for each indicator light color. These applicable regulations
may be different in different geographical regions. As a result, an
automobile that is "street legal" in Europe may fail to meet regulatory
standards in the United States, or vice versa. These regulatory
differences have spawned a lucrative market for high end automobile
importers, which charge substantial fees for retrofitting the indicator
lighting and other features of an imported automobile to comply with road
regulations of the receiving country.

[0006] Even in the absence of regulatory constraints, the automobile
manufacturer may wish to adapt the colors of the indicator lights to
specific markets. For example, anecdotal evidence in the lighting
industry suggests that in some countries illumination lamps that output a
"cool white" light sell better than lamps producing "warm white" light;
whereas, in the other countries lamps producing warm white light tend to
outsell those producing cool white light. Similar local preferences may
exist for automotive indicator lighting, influenced by factors such as
"average" local visibility (typically high in a dry desert climate but
lower in higher-humidity climates), the extent of artificial roadway
lighting infrastructure, or so forth.

[0007] For vehicle manufacturers operating in a global marketplace,
regional differences in regulatory standards and/or customer preferences
complicate manufacturing and increase costs, as the manufacturer must
employ different indicator light assemblies for automobiles intended for
sale in various different geographical markets. This in turn means
maintaining different stock keeping unit (SKU) lines for different
regional taillight variations, which increases inventory, requires
parallel supply lines for the different SKU lines, and restricts vehicle
manufacturing and delivery flexibility.

[0008] Existing automobile indicator lights have additional deficiencies.
For example, in spite of their complexity, the actual informational
content provided by existing taillight assemblies is rather limited. A
following driver is warned of braking by activation of the brake light,
but is given no indication of whether the vehicle ahead is slowing down
gently, or engaging in a panic stop. Indeed, existing commercial
taillight assemblies provide no information about speed changes other
than braking. Proposals exist to indicate "hard" braking by a mechanism
such as blinking red brake lights, or blinking both amber turn indicators
(if amber lights are used for the turn indicators). The former approach
(blinking red brake lights) has the disadvantage that it could be
confused with a slow braking event in which the driver taps the brake
pedal several times (thus producing a "blinking" of the brake light).

[0009] One way to provide additional information is via light intensity
changes. A change in the red light intensity is already used to indicate
braking when the taillights are on. However, employing light intensity
changes to convey additional information to other road users is
problematic. One difficulty is that the visually perceived light
intensity depends upon numerous factors besides the actual radiation
output. These include: the intensity and source position of ambient
lighting; atmospheric conditions; visual acuity of the perceiving road
user; whether the perceiving road user is viewing directly or through a
windshield or windscreen, and if the latter the transmissivity of the
windshield or windscreen; the angle and distance from which the road user
views the indicator light; and so forth. Using light intensity to convey
analog information (such as how strongly the brakes are being applied, or
the vehicle speed or acceleration rate) is therefore problematic, because
it is difficult for other road users to gauge the absolute light
intensity. Another problem with using variable light intensity to convey
information is that the lowest end of the light intensity range may be
visually imperceptible for some viewers.

[0010] Flashing a light on and off can also be used to provide
information, as in a flashing turn indicator. Again, however, number of
different kinds of information that can be intuitively conveyed by the
flashing of lights is limited.

[0011] Another possible way to provide additional information is to
provide additional indicator lights of different colors. For example, the
inclusion of a rearward-facing green light to indicate acceleration was
proposed at least as far back as the early 1940's (see Rodrick, U.S. Pat.
No. 2,301,583). A green acceleration indicator light has not yet been
adopted by any substantial geographical region, and some jurisdictions
prohibit the use of colors other than red (and perhaps amber for turn
signaling or white to indicate backup) in rearward facing vehicle signal
lights. Thus, the adoption of green (or other "nonstandard" colors) is
likely to occur, if at all, on a limited geographical basis.

[0012] The adoption of "new" signal lights, such as a green acceleration
light, into existing vehicle signal lighting schemes is hindered by
numerous factors. Cost is one issue. A typical taillight assembly already
typically includes at least three different indicator lights (red,
yellow, and white). Adding lights of additional colors would further add
to vehicle manufacturing cost. The use of new signal lights is also
hindered by government regulations, which can be slow to change and are
highly region-specific. A new signal light must be "street-legal" in
substantial geographical area (such as the United States, Europe, or so
forth) in order to justify mass manufacturing of vehicles with the new
signal light.

[0013] A relatively recent development in vehicle signal lighting has been
a gradual replacement of incandescent signal lamps with light emitting
diode (LED)-based signal lamps. For example, a red tail or brake
incandescent lamp can be replaced by a red LED-based lamp, which provides
faster light run-up time, higher electrical energy efficiency, improved
operational lifetime and robustness against failure, and may reduce
manufacturing cost. However, replacement of an incandescent lamp with an
LED lamp does not reduce the multiplicity of different taillight assembly
SKU lines needed for different geographical regions, and does not
facilitate the adoption of new signal lights.

[0014] LED-based lamps have also been used to enhance aesthetic automotive
design, for example by integrating LED lamps of different colors on a
common substrate (see, e.g. Lawrence et al., U.S. 2005/0254240), and
using flexible substrates to design LED taillight assemblies that conform
with vehicle curvature (Chen, et al., U.S. Pat. No. 6,520,669). The use
of an LED signal lamp that can selectively emit one of two or more
different colors has also been proposed, so as to reduce the number of
signal lamps. For example, Abbe et al., U.S. Pat. No. 6,714,128 discloses
a "smart light" that includes a set of red LEDs and a set of amber LEDs
with a controller that selectively operates either the red LEDs or the
amber LEDs so as to enable the "smart light" to be selectively used as
either a red taillight or brake light or as an amber turn indicator. This
amounts to a tight integration of red and amber LED-based lamps on a
common substrate together with integral control electronics.

[0015] However, these developments still do not reduce the multiplicity of
different taillight assembly SKU lines needed to accommodate the various
different regional signal light standards. Indeed, by integrating red and
amber LED lamps on a common substrate, the number of different SKU lines
required to accommodate different regional regulations or preferences may
increase, since a difference in any one signal lamp of the integral
assembly of signal lamps will require a new SKU line. These developments
also do not facilitate the adoption of new signal lights.

BRIEF SUMMARY

[0016] In some illustrative embodiments disclosed herein, a vehicle signal
light assembly includes: at least one color mixing light source; a
support element configured to support the at least one color mixing light
source on a vehicle as a signal light; and a controller configured to
selectively drive each color mixing light source to generate light of a
selected visually perceived color based on a received control signal. In
some such embodiments, each color mixing light source of the vehicle
signal light assembly comprises a plurality of light emitting diodes
(LEDs) of at least two constituent colors. In some such embodiments, the
controller is configured to operate each color mixing light source of the
vehicle signal light assembly using time domain multiplexing (TDM) to
generate the light of the selected visually perceived color. In some such
embodiments, the vehicle signal light assembly comprises a taillight
assembly.

[0017] In some illustrative embodiments disclosed herein, an apparatus is
disclosed, including a vehicle, and a vehicle signal light assembly as
set forth in the immediately preceding paragraph, wherein the vehicle
signal light assembly is supported by the support element on the vehicle
and the controller is operatively connected with the vehicle to operate
the vehicle signal light assembly based on a control signal received from
the vehicle.

[0018] In some illustrative embodiments disclosed herein, a method is
disclosed, comprising generating a vehicle signal emanating from a
vehicle by: emitting signaling light of a first visually perceived color
responsive to a first control signal using a color mixing light source
mounted on the vehicle, the signaling light of the first visually
perceived color comprising a mixture of light of at least two different
colors generated by the color mixing light source; and emitting signaling
light of a second visually perceived color responsive to a second control
signal using the color mixing light source mounted on the vehicle, the
second visually perceived color being different from the first visually
perceived color.

[0019] In some illustrative embodiments disclosed herein, a taillight
assembly is disclosed, the taillight including a color mixing light
source and a controller configured to drive the color mixing light source
to generate light of a selected one of at least two different selectable
visually perceived colors based on a control signal received by the
taillight assembly from the vehicle. In some such embodiments, the
controller is configured to drive the color mixing light source to
generate light of a selected one of at least two different selectable
visually perceived colors using time-domain multiplexing (TDM) mixing of
light of at least two different constituent colors.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The invention may take form in various components and arrangements
of components, and in various process operations and arrangements of
process operations. The drawings are only for purposes of illustrating
preferred embodiments and are not to be construed as limiting the
invention.

[0027]FIG. 7 diagrammatically illustrates a timing diagram for operation
of the adjustable color illumination system of FIG. 6.

[0028]FIG. 8 diagrammatically illustrates a flow chart for operation of
the adjustable color illumination system of FIG. 6.

[0029] FIG. 9 diagrammatically shows a rear view of an automobile
including illustrative left and right taillight assemblies.

[0030] FIG. 10 diagrammatically shows a perspective view of the left
taillight assembly of the automobile of FIG. 9.

[0031]FIG. 11 diagrammatically shows an electrical block diagram of the
left taillight assembly of FIG. 10.

[0032]FIG. 12 plots a color point adjustment for red tail and/or red
brake signal lighting as a function of a humidity measurement signal.

[0033] FIGS. 13 and 14 diagrammatically show a rear view of an automobile
including additional illustrative left and right taillight assemblies.

[0034]FIG. 15 diagrammatically shows a rear view of an automobile
including functionally asymmetric left and right taillight assemblies.

[0035] FIG. 16 diagrammatically shows a single SKU line taillight assembly
that can function as either the left or right asymmetric taillight
assembly of FIG. 15.

[0036] FIGS. 17 and 18 diagrammatically show a modular configuration in
which the taillight assembly includes a color mixing light source array
module optically coupled with different optical modules for different
vehicle makes/models.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0037] The term "light emitting diode" or "LED" as used herein denotes a
compact solid-state light emitting device, and encompasses
semiconductor-based LEDs (optionally including integral phosphor),
organic LEDs (sometimes represented in the art by the acronym OLED),
semiconductor laser diodes, or so forth. The terms "light emitting diode"
or "LED" as used herein does not encompass incandescent light bulbs,
fluorescent light tubes, halogen bulbs, high intensity or discharge (HID)
lamps that incorporate an evacuated volume or a fluid (that is, gaseous
or liquid) component.

[0038] The phrase "color LED" denotes an LED that emits light of the
specified color. For example, a red LED emits red light; a white LED
emits white light ("color" as used herein is to be broadly construed as
encompassing white); a green LED emits green light; and so forth. In some
instances a color LED may not appear visually to have the specified color
when not operational--for example, some red LEDs do not appear visually
as red objects when not operational. A "white LED" may in some
embodiments comprise a semiconductor chip emitting ultraviolet or violet
light coated with a white-fluorescing phosphor, such that the combination
emits white light. In other embodiments, a "white LED" may comprise three
semiconductor chips arranged in close proximity that emit red, blue, and
green light, respectively, and are electrically interconnected and
mounted as a single device package emitting white light. Also, note that
the terms "yellow" and "amber" are used interchangeably herein.

[0039] The vehicle indicator lights disclosed herein utilize color mixing
light sources. A color mixing light source, as that term is used herein,
encompasses a light source that includes a plurality of interspersed
pluralities of light emitting diodes (LEDs) including at least a first
plurality of LEDs emitting light of a first color and an interspersed
second plurality of LEDs emitting light of a second color different from
the first color. For example, in some embodiments the first plurality of
LEDs may emit red light and the second plurality of LEDs may emit yellow
or amber light. In some other embodiments, the first plurality of LEDs
may emit red light, the second plurality of LEDs may emit green light,
and a third plurality of LEDs may emit blue light. The LEDs of the color
mixing light source are arranged in an interspersed fashion so that light
from the various pluralities of LEDs mix together when illuminated. The
color mixing light source optionally also includes a lens, reflector,
light guide, or other optics or combination of optics for mixing,
collimating, diverging, or otherwise shaping or adjusting the light. If
the pluralities of LEDs emit red, green, and blue light, then the mixture
can in the proper proportions correspond to white light. As used herein,
"white light" is considered a color of light. In one suitable
arrangement, the LEDs include red, green, and blue LEDs.

[0040] Two or more pluralities of LEDs of the color mixing light source
can generate mixed light that is a combination of the source colors
(additive color mixing). The term "visually perceived light" is used to
denote the light visually observed to be output by the color mixing light
source. Color mixing light sources can employ various color mixing
schemes, such as pulse-width modulation (PWM), pulse frequency modulation
(PFM), pulse amplitude modulation (PAM), continuous d.c. or a.c. control,
and so forth. For example, Chliwnyj et al., U.S. Pat. No. 5,924,784
discloses a color mixing light source comprising independent
microprocessor-based PWM control of two or more different color LEDs to
generate light simulating a flame. Such PWM control is well known, and
commercial PWM controllers are available for driving LEDs using PWM. See,
e.g., Motorola Semiconductor Technical Data Sheet for MC68HC05D9 8-bit
microcomputer with PWM outputs and LED drive (Motorola Ltd., 1990). In
PWM, a train of pulses is applied at a fixed frequency, and the pulse
width (that is, the time duration of the pulse) is modulated to control
the time-integrated power applied to the LED. Accordingly, the
time-integrated applied power is directly proportional to the pulse
width, which can range between 0% duty cycle (no power applied) to 100%
duty cycle (power applied during the entire period). In PFM, the pulse
width is fixed and the repetition rate of pulses is varied to control the
time-integrated power applied to the LED. In PAM, both the pulse duration
and repetition frequency are fixed, and the pulse amplitude is varied to
control the time-integrated power applied to the LED.

[0041] As used herein, the term "color mixing light source" can employ any
color mixing scheme, including but not limited to PWM, PFM, PAM,
continuous d.c. or a.c. control.

[0042] Another aspect of a color mixing light source as that term is used
herein is that the color of light output by the color mixing light source
can be changed or adjusted by changing the relative intensities of the
constituent interspersed pluralities of LEDs. Thus, a white light source
that merely uses interspersed red, green, and blue LEDs to generate white
light, without a controller for adjusting the relative ratios of the red,
green, and blue intensities to achieve color changing or color
adjustment, is not a color mixing light source as that term is used
herein.

[0043] With reference to FIGS. 1-8, an illustrative color mixing scheme
employing time-domain multiplexing (TDM) is described. In the disclosed
TDM approach, the pulse width for each color channel is varied (as in
PWM), but the start time of each pulse for each channel is also adjusted
such that only one channel is operational at any given time. Thus, the
different colors are generated sequentially in TDM, but at a switching
rate fast enough so that the eye "mixes" the colors to generate the
visually perceived light as a time-integrated mixture. As disclosed
herein, the TDM scheme can enable constant power draw, thus facilitating
energy efficiency and reducing stress on the power source due to load
changes.

[0044] With reference to FIG. 1, an illustrative color mixing light source
10 includes red, green, and blue light emitting diodes (LEDs). The red
LEDs are electrically interconnected (circuitry not shown) to be driven
by a red input line R. The green LEDs are electrically interconnected
(circuitry not shown) to be driven by a green input line G. The blue LEDs
are electrically interconnected (circuitry not shown) to be driven by a
blue input line B. The light source 10 is an illustrative example; in
general the light source can be any multi-color light source having sets
of solid state light sources electrically interconnected to define
different color channels. In some embodiments, for example, the red,
green, and blue LEDs are arranged as red, green, and blue LED strings.
Moreover, the different colors can be other than red, green, and blue,
and there can be more or fewer than three different color channels. For
example, in some embodiments a blue channel and a yellow channel are
provided, which enables generation of various different colors that span
a color range less than that of a full-color RGB light source, but
including a "whitish" color achievable by suitable blending of the blue
and yellow channels. The individual LEDs are diagrammatically shown as
black, gray, and white dots in the light source 10 of FIG. 1.

[0045] The light source 10 is driven by a constant current power source
12. By "constant current" it is meant that the power source 12 outputs a
constant rms root-mean-square) current. In some embodiments the constant
rms current is a constant d.c. current. However, the constant rms current
can be a sinusoidal current with a constant rms value, or so forth. The
"constant current" is optionally adjustable, but it is to be understood
that the current output by the constant current power source 12 is not
cycled rapidly as is the case for PWM. The output of the constant current
power source 12 is input to a R/G/B switch 14 which acts as a
demultiplexor or one-to-three switch to channel the constant current into
one, and only one, of the three color channels R, G, B at any given time.

[0046] The basic concept of the color control achieved using the constant
current power source 12 and the R/G/B switch 14 is illustrated by a
timing diagram shown in FIG. 2. The switching of the R/G/B switch 14 is
performed over a time interval T, which is divided into three time
sub-intervals defined by fractional periods f1×T,
f2×T, and f3×T where f1+f2+f3=1 and
accordingly the three time periods obey the relationship
f1×T+f2×T+f3×T=T. A color controller 16
outputs a control signal indicating the fractional periods
f1×T, f2×T, and f3×T. For example, the
color controller 16 may, in an illustrative embodiment, output a two-bit
digital signal having value "00" indicating the fractional time period
f1×T, and switching to a value "01" to indicate the fractional
time period f2×T, and switching to a value "10" to indicate
the fractional time period f3×T, and switching back to "00" to
indicate the next occurrence of the fractional time period
f1×T, and so on. In other embodiments, the control signal can
be an analog control signal (e.g., 0 volts, 0.5 volts, and 1.0 volts
indicating the first, second, and third fractional time periods,
respectively) or can take another format. As yet another illustrative
approach, the control signal can indicate transitions between fractional
time periods, rather than holding a constant value indicative of each
time period. In this latter approach, the R/G/B switch 14 is merely
configured to switch from one channel to the next when it receives a
control pulse, and the color controller 16 outputs a control pulse at
each transition from one fractional time period to the next fractional
time period.

[0047] During the first fractional time period f1×T the R/G/B
switch 14 is set to flow the constant current from the constant current
power source 12 into a first one of the color channels (for example, into
the red channel R). As a result, the light source 10 generates only red
light during the first fractional time period f1×T. During the
second fractional time period f2×T the R/G/B switch 14 is set
to flow the constant current from the constant current power source 12
into a second one of the color channels (for example, into the green
channel G). As a result, the light source 10 generates only green light
during the second fractional time period f2×T. During the
third fractional time period f3×T the R/G/B switch 14 is set
to flow the constant current from the constant current power source 12
into a third one of the color channels (for example, into the blue
channel B). As a result, the light source 10 generates only blue light
during the third fractional time period f3×T. As indicated in
FIG. 2, this cycle repeats with the time period T.

[0048] The time period T is selected to be shorter than the flicker fusion
threshold, which is defined herein as the period below which the
flickering caused by the light color switching becomes substantially
visually imperceptible, such that the light is visually perceived as a
substantially constant blended color. That is, T is selected to be short
enough that the human eye blends the light output during the fractional
time intervals f1×T, f2×T, and f3×T so
that the human eye perceives a uniform blended color. Insofar as PWM also
is based on the concept of visual blending of rapidly cycled light of
different colors, the period T should be comparable to the pulse period
used in PWM which is also below the flicker fusion threshold, for example
below about 1/10 second, and preferably below about 1/24 second, and more
preferably below about 1/30 second, or still shorter. A lower limit on
the time period T is imposed by the switching speed of the R/G/B switch
14, which can be quite fast since its operation does not entail changing
current levels (as is the case for PWM).

[0049] Quantitatively, the color can be computed as follows. The total
energy of red light output by the red LEDs during the first fractional
time interval f1×T is given by a1×f1×T;
the total energy of green light output by the green LEDs during the
second fractional time interval f2×T is given by
a2×f2×T; and the total energy of blue light output
by the blue LEDs during the third fractional time interval
f3×T is given by a3×f1×T; where the
constants a1, a3 are indicative of the relative efficiencies of
the sets of red, green, and blue LEDs, respectively. For example, if for
a given electrical current the light energy output by the set of red LEDs
equals the light energy output by the set of green LEDs equals the light
energy output by the set of blue LEDs, then a proportionality of
a1:a2:a3 is appropriate. On the other hand, if the set of
blue LEDs outputs twice as much light for a given electrical current
level as compared with the other sets of LEDs, then a proportionality of
2×a1:2×a2:a3 is appropriate. Optionally, the
constants a1, a2, a3 represent the relative visually
perceived brightness levels, rather than the relative photometric energy
levels. The color is determined by the proportionality of the red, green,
and blue light energy outputs, i.e. by the proportionality of
a1×f1×T: a2×f2×T:
a3×f3×T or more simply a1×f1:
a2×f2: a3×f3.

[0050] For example, in illustrative FIG. 2 f1:f2:f3 is
2:3:1 which (taking a1=a2=a3 for simplicity) means that
the relative ratio of red:green:blue is 2:3:1. If the fractional periods
had proportionality f1:f2:f3=1:1:1 then (again taking
a1=a2=a3 for simplicity) the light output would be
visually perceived as an equal blending of red, green, and blue light,
which is to say the light output would be white light.

[0051] Advantageously, the current output by the constant current power
source 12 into the light source 10 remains the same at all times. In
other words, from the viewpoint of the constant current power source 12,
it is outputting a constant current to the load comprising the components
10, 14.

[0052] In some embodiments the switching between fractional time periods
performed by the color controller 16 is done in an open-loop fashion,
that is, without reliance upon optical feedback. In these embodiments, a
look-up table, stored mathematical curves, or other stored information
associates values of proportionality of the fractional ratios
f1:f2:f3 with various colors. For example, if
a1=a2:a3 then the values f1=f2=f3=1/3 is
suitably associated with the "color" white.

[0053] With continuing reference to FIG. 1 and with further reference to
FIGS. 3 and 4, in other embodiments the color is optionally controlled
using optical feedback as follows. A photosensor 20 monitors the light
power output by the light source 10. The photosensor 20 is of
sufficiently broad wavelength to sense any of the red, green, or blue
light. For simplicity, it is assumed herein that the photosensor 20 has
equal sensitivity for red, green, and blue light--if this is not the
case, it is straightforward to incorporate a suitable scaling factor to
compensate for spectral sensitivity differences. FIG. 3 illustrates a
suitable optical power measurement process performed by a R, G, B energy
meter 22. At a start 30 of a first color fractional period (i.e., the
start of the fractional period f1×T), an optical power
measurement is initiated. The measured optical power is integrated 32
over the first fractional period f1×T to generate a measured
first color energy 34. Note that because only one set of LEDs of a single
color (e.g., red) is operating during the first fractional period
f1×T, the broadband photosensor 20 measures only red light
during the time interval of the integration 32. At a transition 40 to the
second fractional time interval f2×T, a second optical power
integration 42 is initiated which extends over the second fractional time
period f2×T in order to generate a measured second color
energy 44. Again, because only one set of LEDs of a single color (e.g.,
green) is operating during the second fractional period f2×T,
the broadband photosensor 20 measures only green light during the time
interval of the integration 42. At a transition 50 to the third
fractional time interval f3×T, a third optical power
integration 52 is initiated which extends over the third fractional time
period f3×T in order to generate a measured third color energy
54. Yet again, because only one set of LEDs of a single color (e.g.,
blue) is operating during the third fractional period f3×T,
the broadband photosensor 20 measures only blue light during the time
interval of the integration 52.

[0054] Thus, it is seen that the single broadband photosensor 20 is
capable of generating all three of the measured first color energy 34,
the measured second color energy 44, and the measured third color energy
54. This is achieved because the control system 12, 14, 16 ensures that
only a single set of LEDs of a single color are operational at any given
time. In contrast, with existing PWM system two or more sets of LEDs of
different colors may be operational at the same time, which then dictates
that different narrowband photosensors centered on the different colors
are used to simultaneously disambiguate and measure the light of the
different colors.

[0055] With reference to FIG. 4, the color controller 16 suitably uses the
measured color energies 34, 44, 54 to implement feedback color control as
follows. The first measured color energy 34 is denoted herein as
EM1. The second measured color energy 44 is denoted herein as The
third measured color energy 34 is denoted herein as EM3. The
measured color is then suitably represented by the ratio
EM1:EM2:EM3. The measured color was achieved using a set
of fractional time intervals represented by the proportionality
f1.sup.(n):f2.sup.(n):f3.sup.(n), where the superscript
(n) denotes the nth interval of time period T during which the
integrations 32, 42, 52 generated the measured color energies 34, 44, 54.

[0056] A desired or setpoint color 60 is suitably represented by the ratio
ES1:ES2:ES3. A periods adjuster 62 computes adjusted of
fractional time intervals 64 represented herein by the proportionality
f1.sup.(n+1):f2.sup.(n+1): f3.sup.(n+1), where the
superscript (n+1) denotes the next interval of time period T which is to
be divided into the subintervals f1.sup.(n+1)×T,
f2.sup.(n+1)×T, and f1.sup.(n+1)×T, subject to the
constraint f1.sup.(n+1)+f2.sup.(n+1)+f3.sup.(n+1)=1. It is
also known that f1.sup.(n)+f2.sup.(n)+f3.sup.(n)=1. The
solution is suitably computed using ratios, for example:

which along with the relationship constraint
f1.sup.(n+1)+f2.sup.(n+1)+f1.sup.(n+1)=1 provides a set of
equations in which all parameters are known except the updated fractional
time intervals f1.sup.(n+1), f2.sup.(n+1), and
f3.sup.(n+1) 64. The updated fractional time intervals
f1.sup.(n+1), f2.sup.(n+1), and f3.sup.(n+1) 64 are
suitably computed by simultaneous solution of this set of Equations.

[0057] In other embodiments, iterative adjustments are used to iteratively
adjust the measured optical energies ratio EM1:EM2:EM3
toward the color setpoint 60 given by the desired energies ratio
ES1:ES2:ES3. For example, in one iterative approach
whichever measured energy has the largest deviation from its setpoint
energy is adjusted proportionately. For example, if the first measured
energy 34 deviates most strongly, then the adjustment
f1.sup.(n+1)=(ES1/EM1)×f1.sup.(n) is made. The
remaining two fractional time intervals are then adjusted to ensure the
condition f1.sup.(n+1)+f2.sup.(n+1)+f3.sup.(n+1)=1 is
satisfied. This adjustments repeated for each time interval T to
iteratively adjust toward the setpoint color 60.

[0058] These are merely illustrative examples, and other algorithms can be
used to adjust the fractions f1, f2, f3 based on the
feedback measured color energies 34, 44, 54 to achieve the setpoint color
60. Moreover, in some embodiments the integrators 32, 42, 52 are omitted
and instead the instantaneous power is measured using the photosensor 20.
The energy is then calculated by multiplying the instantaneous power
times the fractional time interval f1×T (for the first
fractional time interval), assuming that the measured instantaneous power
is constant over the fractional time interval. Moreover, in some
embodiments the measured color energy is represented not as a photometric
value but rather as a visually perceived brightness level, by scaling the
photometric values measured by the photosensor 20 by the optical
response, which is known to be spectrally varying. As used herein, "color
energy" is intended to encompass either photometric values or visually
perceived brightness levels.

[0059] The constant current power source 12 generates a constant current
on the timescale of the time interval T for cycling the R/G/B switch 14.
However, it is contemplated to adjust the electrical current level to
achieve overall intensity variation for the adjustable color light source
10. Such adjustment is suitably performed using a current controller 70
in an open-loop fashion, in which the electrical current level is set in
an open-loop fashion using a manual current control dial input, an
automatically controlled electrical signal input, or so forth. Note that
because the color control operates on a ratio basis (even when using
optional optical feedback as described with reference to FIGS. 3 and 4),
adjustment of the current level of the constant current source on a time
scale substantially larger than the time interval T for the R/G/B cycling
has little or no impact on the color control.

[0060] With continuing reference to FIG. 1 and with further reference to
FIG. 5, in some embodiments, it is contemplated for the current
controller 70 to operate in an optical feedback-controlled mode to
achieve a light intensity output corresponding to a setpoint intensity
Eset 72. In the illustrated feedback-controlled intensity approach,
the feedback measured color energies 34, 44, 54 are summed together by an
adder 74 to generate a total measured energy Etot 76 that is input
to a current adjuster 78 that adjusts the electrical current level 80 of
the constant current power source 12 to achieve or approximate the
condition Eset=Etot. The current adjuster 78 can, for example,
employ a digital proportional-integral-derivative (PID) control algorithm
to adjust the electrical current level 80.

[0061] The illustrated embodiments include three color channels, namely R,
G, B. However, more or fewer channels can be employed. For n=1, . . . , N
channels where N is a positive integer and N>1, the time interval T is
divided into N time intervals f1×T, . . . , fN×T
under the condition f1+ . . . +fN=1 where the fractions
f1, . . . , fN are all positive values in the interval [0,1],
and the switch 14 is a one-to-N switch.

[0062] In the case in which one of the channels is to be off entirely,
that is, fn=0, this can be achieved either by having the switch 14
bypass that color channel entirely, or by setting fn=δ where
δ is a value sufficiently small that the color corresponding to
fn=δ is not visually perceived.

[0063] The term "color" as used herein is to be broadly construed as any
visually perceptible color. The term "color" is to be construed as
including white, and is not to be construed as limited to primary colors.
The term "color" may refer, for example, to an LED that outputs two or
more distinct spectral peaks (for example, an LED package including red
and yellow LEDs to achieve an orange-like color having distinct red and
yellow spectral peaks). The term "color" may refer, for example, to an
LED that outputs a broad spectrum of light, such as an LED package
including a broadband phosphor that is excited by photons produced by
electroluminescence from a semiconductor chip. An "adjustable color light
source" as used herein is to be broadly construed as any light source
that can selectively output light of different spectra. An adjustable
color light source is not limited to a light source providing full color
selection. For example, in some embodiments an adjustable color light
source may provide only white light, but the white light is adjustable in
terms of color temperature, color rendering characteristics, or so forth.

[0064] With reference to FIGS. 6-8, another illustrative embodiment is
shown as an example. FIG. 6 shows an adjustable color light source in the
form of a set of three series-connected strings S1, S2, S3 of five LEDs
each. The first string S1 includes three LEDs emitting at a peak
wavelength of about 617 mm, corresponding to a shallow red, and two
additional LEDs emitting at a peak wavelength of about 627 nm,
corresponding to a deeper red. The second string S2 includes five LEDs
emitting at 530 nm, corresponding to green. The third string S3 includes
four LEDs emitting at a peak wavelength of about 590 nm, corresponding to
amber, and one additional LED emitting at a peak wavelength of about 455
nm, corresponding to blue. Drive and control circuitry includes a
constant current source CC and three transistors with inputs R1, G1, B1
arranged to block or allow current flow through the first, second, and
third LED strings S1, S2, 53, respectively. Additionally, a transistor
with input R2 enables the two deeper red (627 nm) LEDs to be selectively
shunted, while a transistor with input B2 enables the blue (455 nm) LED
to be selectively shunted. An operational state table for the adjustable
color light source of FIG. 6 is given in Table 1. Note that the channel
color listed for each channel is qualitative, and may be subjectively
adjudged differently by different observers. The operational control is
configured such that only one of the three LED strings S1, S2, S3 is
driven at any given time; accordingly, the same current flows through the
617 nm LEDs of string S1 regardless of whether the R2 transistor is in
the conducting or nonconducting state; and similarly the same current
flows through the 590 nm LEDs of string S3 regardless of whether the B2
transistor is in the conducting or nonconducting state.

[0065]FIG. 7 plots the timing diagram for operation of the adjustable
color illumination system of FIG. 6. The LED wavelengths or colors of the
adjustable color illumination system of FIG. 6 are not selected to
provide adjustable full-color illumination, but rather are selected to
provide white light of varying quality, for example warm white light
(biased toward the red) or cold white light (biased toward the blue). The
adjustable color illumination system of FIG. 6 has five color channels as
labeled in Table 1. In illustrative FIG. 7 the five transistors are
operated to provide a one-to-five switch operating over a time interval T
which in FIG. 7 is 1/150 sec (6.67 ms) in accordance with a selected time
division of the time interval T to generate white light with selected
quality or characteristics. The time interval T= 1/150 sec is shorter
than the flicker fusion threshold for a typical viewer. The time interval
T is time-division multiplexed into five fractional time periods T1, T2,
T3, T4, T5 where the five fractional time periods T1, T2, T3, T4, T5 are
non-overlapping and sum to the time interval T, that is,
T=T1+T2+T3+T4+T5. In the embodiment of FIG. 7, the color energy
measurement for each color channel is acquired at an intermediate time
substantially centered within each fractional time period, as indicated
in FIG. 7 by the notations "E( . . . nm)" indicating the operating
wavelengths at each color energy measurement.

[0066] With reference to FIG. 8, a control process suitably implemented by
the control circuitry including the five transistors shown in FIG. 6 is
illustrated. At a starting time 100 existing time values for the
fractional time periods T1, T2, T3, T4, T5 are loaded 102 into a
controller. This is followed by successive operations 104, 106, 108, 110,
112 initiate the five fractional time periods T1, T2, T3, T4, T5 in
succession and perform energy measurements using a single photosensor. A
calculation block 114 uses the measurements to compute updated values for
the fractional time periods T1, T2, T3, T4, T5. For example, the
relationship [E1T1]/[E2T2]=C12 where C12 is a constant
reflecting the desired red/deep red color ratio is suitably used to
constrain the fractional time periods T1 and T2; the relationship
[E2T2]/[E3T3]=C23 where C23 is a constant reflecting the
desired deep red/green color ratio is suitably used to constrain the
fractional time periods T2 and T3; the relationship
[E3T3]/[E4T4]=C34 where C34 is a constant reflecting the
desired green/blue-amber color ratio is suitably used to constrain the
fractional time periods T3 and T4; and the relationship
[E4T4]/[E5T5]=C45 where C45 is a constant reflecting the
desired blue-amber/amber color ratio is suitably used to constrain the
fractional time periods T4 and T5. The calculation block 114 suitably
simultaneously solves these four equations along with the constraint
T=T1+T2+T3+T4+T5 to obtain the updated values for the fractional time
periods T1, T2, T3, T4, T5. In some embodiments, the calculation block
114 operates in the background in an asynchronous fashion respective to
the cycling of the light source at the time interval T. To accommodate
such asynchronous operation, a decision block 120 monitors the
calculation block 114 and continues to load existing timing values 102
until the updated or new timing values are output by the calculation
block 114, at which time the new timing values are loaded 122.

[0067] It will be appreciated from the example of FIGS. 6-8 that the
time-division multiplexing does not necessarily require that the LEDs be
allocated in an exclusive manner between the fractional time periods. In
the embodiment of FIGS. 6-8, for example, the amber LEDs emitting at 590
nm are operational during both the fourth fractional time period T4 and
the fifth fractional time period T5. The embodiment of FIGS. 6-8 also
illustrates that the color channels can correspond to different shades
(e.g., shallow red versus deeper red), and that a given color channel may
emit light of two or more distinct peaks at different colors (for
example, during the fractional time period T4 both amber light peaked at
590 nm and blue light peaked at 455 nm are emitted).

[0068] Having described the illustrative TDM color mixing scheme, the
application of color mixing light sources to vehicle signal lighting is
next addressed with reference to FIGS. 9-16. It is emphasized that the
TDM color mixing scheme is described herein merely as an illustrative
example. In general, the disclosed vehicle signal lighting assemblies
including one or more color mixing light sources can employ any color
mixing scheme, including but not limited to TDM, PWM, PFM, PAM,
continuous d.c. or a.c. control, or so forth.

[0069] Color mixing light sources are typically used in applications that
call for providing illumination of a number of different discrete colors,
or that call for providing illumination of continuously or
quasi-continuously variable color. For example, theatre lighting
comprising color mixing light sources are known. In contrast, regulatory
standards impose strict constraints on the allowable colors used in
vehicle signal lights. For example, a taillight or a brake light is
typically required to be red, and only red, while a turn indicator signal
is typically required to be yellow in Europe, or either yellow or red in
the United States. Backup lights are typically required to be white.
Similarly restrictive color palettes are typically imposed on other
vehicle signal lights, such as side signal lighting. It is known in the
art that employing a limited and uniform palette of colors for signal
lighting, with each color indicating one or, at most, a small number of
different signals, enhances the likelihood that other road users will
rapidly and accurately discern the meaning of a vehicle signal light.

[0070] Moreover, using color mixing light sources for vehicle signal
lighting can be expected to increase the per-unit signaling light
assembly cost as compared with using single-color incandescent or LED
lamps, due to the relatively higher complexity and number of components
in a color mixing light source. The vehicle manufacturing industry is
highly competitive and cost conscious.

[0071] It is recognized herein, however, that color mixing light sources
can nonetheless be used to substantial benefit in vehicle lighting
assemblies. This conclusion is reached by considering the cost benefit
achieved by a reduction in the number of stock keeping unit (SKU) lines
that need to be maintained by a vehicle manufacturer operating on a
global scale. As disclosed herein, a single signal light assembly SKU
line employing one or more color mixing light sources can advantageously
be used in many different geographical regions, even if those regions
have mutually incompatible vehicle signal lighting standards.
Additionally, it is recognized herein that a modular configuration of a
signal light assembly employing a single color mixing light source that
is optically coupled with different optical module constructions can
serve different vehicle makes/models. Moreover, it is recognized herein
that a signal light assembly employing color mixing light sources is
readily reconfigured to incorporate new signal lighting paradigms, such
as an illustrative green "accelerator light". This makes the deployment
of new types of signal lighting cost-effective, even for relatively small
markets. Still further, it is recognized herein that a signal light
assembly employing at least one color mixing light source is readily
configured to be adjustable in real-time in response to changing
environmental conditions. For example, disclosed real-time adjustment of
the "shade" or "hue" or, more generally, the color point, of a red tail
light or brake light enables the signal to be more readily perceived in
low-visibility driving conditions. In addition, it is recognized herein
that a signal light assembly employing a single color mixing light source
can generate intensified level of light signal by changing the area ratio
dedicated for the different signaling functions of the signal light
assembly.

[0072] With reference to FIG. 9, a rear view of a vehicle 150 is shown.
The depicted rear view shows the roof 152, left- and right-side window
lines 154, 156, a rear window 158, a trunk 160, and left and right rear
tires 162, 164. The illustrative vehicle 150 also includes other
components not visible in the rear view, such as a hood, front tires,
front and side windows, front headlights, and so forth, as well as
internal components such as an engine (which may be diesel, gasoline,
electric, gasoline/hybrid electric, or so forth), transmission, emissions
system, and so forth. These components are not illustrated, but are well
known in the art. Moreover, while the illustrated vehicle 150 is an
automobile, it is to be understood that the vehicle can also be a pickup,
hatchback vehicle, sport-utility vehicle (SUV), commercial truck,
semi-trailor truck or tractor trailor (sometimes known as a "semi" or "18
wheeler", although the number of wheels can be other than eighteen), road
plow, snowmobile, motorcycle, scooter, bicycle, tricycle, or other
vehicle for which the disclosed vehicle signal light assemblies may be
useful.

[0073] The vehicle 150 includes various signal light assemblies, of which
a left taillight assembly 170, right taillight assembly 172, and center
taillight assembly 174 are visible in the depicted rear view. Other
signal light assemblies that are typically included on at least some
vehicles, but which are not visible in the rear view, include side
lighting assemblies, front indicator/parking light assemblies, and so
forth. The illustrated left and right taillight assemblies 170, 172 are
generally similar except for having a bilateral reflection symmetry about
a vertical plane; accordingly, the left taillight assembly 170 is
described in some detail herein, with it being understood that the
description also applies in substance to the right taillight assembly
172.

[0074] With reference to FIG. 10, a detailed perspective view of the left
taillight assembly 170 is shown. The left taillight assembly 170 includes
a plurality of color mixing light sources V, W, X, Y, Z disposed on a
support element 180 configured to support the color mixing light sources
V, W, X, Y, Z on the vehicle 150 as a signal light, and specifically in
the illustrated embodiment as a left taillight. The support element 180
is mechanically configured, that is, appropriately sized and shaped, to
fit into a receiving receptacle (not shown) at the rear end of the
vehicle 150. In other embodiments, the support element may take other
shapes and configurations designed to mount in or on an end or side of
the vehicle. The support element may be specific to a particular make or
model of vehicle, or may be specific to a particular manufacturing year
of a particular vehicle make and model. On the other hand, if the
manufacturer uses a common signal light receptacle design for a range of
models, then the support element may be suitably installed in any vehicle
of that range of compatible models. In some embodiments, the support
element may be configured as a retrofit unit shaped and sized to retrofit
into a mount or receptacle designed to hold an incandescent lamp-based
signal light assembly or other "original equipment manufacturer" signal
light assembly.

[0075] The support element 180 is also electrically configured to mate
with electrical taillight assembly connections of the vehicle 150. Toward
this end, the illustrated support element 180 includes a pigtail 182 with
distal connectors 184 sized, shaped, of suitable electrical conductor
wire gauge, and otherwise electrically and structurally configured to
mate with taillight assembly control signal and power connectors of the
vehicle 150 (not shown). While a pigtail connector assembly 182, 184 is
illustrated, in other embodiments the connector assembly may comprise a
socket or other suitable electrical connector configuration. In some
embodiments, the support element 180 may provide electrical ground or
otherwise be incorporated into the electrical configuration of the
taillight assembly 170.

[0076] Each of the illustrated color mixing light sources V, W, X, Y, Z
disposed on the support element 180 include a plurality of interspersed
pluralities of LEDs including at least a first plurality of LEDs emitting
light of a first color and an interspersed second plurality of LEDs
emitting light of a second color different from the first color. The LEDs
are not shown in FIG. 10, but it is to be understood that each of the
illustrated color mixing light sources V, W, X, Y, Z may, for example,
have the configuration of the light source 10 shown in FIG. 1 which
includes red, green, and blue LEDs (where it is again emphasized that,
for example, the term "red LED" indicates an LED that emits light of a
red color, and does not necessarily relate to the color of the LED when
nonoperational). In other embodiments, the first, second, and optional
additional pluralities of LEDs may be of different colors so long as the
colors are sufficient to mix to generate signal lighting of the range of
colors desired to be output by the color mixing light source.

[0077] The layout of the plurality of interspersed pluralities of LEDs for
each color mixing light source is selected to provide a desired shape or
area coverage, which in some embodiments may be a non-contiguous shape or
area. For example, the color mixing light source V encompasses two
non-contiguous triangular areas that are separated by the triangular
color mixing light source W. The areas of the two color mixing light
sources W, V are selected to collectively define a left arrow (for the
left taillight assembly 170 as seen in FIGS. 9 and 10) or are selected to
collectively define a right arrow (for the right taillight assembly 172
as seen in FIG. 9). Optionally, a transparent or translucent cover 181
(shown in FIG. 10) may be disposed over the taillight assembly 170. Since
the color mixing light sources V, W, X, Y, Z provide light color control,
the transparent or translucent cover 181 advantageously can be
constructed as a single piece that covers all five light sources V, W, X,
Y, Z. In some contemplated embodiments, all five color mixing light
sources V, W, X, Y, Z are substantially of the same shape constituting an
array of color mixing light sources, while the final geometry of the
radiating areas on the signal light assembly are created by proper
combination of different optical components such as a lens, a reflector,
a light guide or other optics or combination of these for mixing,
collimating, diverging, or otherwise shaping or adjusting the light
emitted by the single individual segments of the array.

[0078] With continuing reference to FIG. 10 and with further reference to
FIG. 11, the taillight assembly 170 also includes a controller 200 that
is configured to independently and selectively drive each plurality of
LEDs of each of the color mixing light sources V, W, X, Y, Z so as to
selectively generate light of at least two different selectable visually
perceived colors. For each color mixing light source, at least one the
selectable visually perceived colors comprises a mixture of at least
light of the first color generated by driving the first plurality of LEDs
and light of the second color generated by driving the second plurality
of LEDs. The independent control signals for the pluralities of red,
green, and blue LEDs of the color mixing light source V are indicated in
FIG. 11 as R(V), G(V), and B(V) respectively, and the control circuitry
for generating these signals is suitably embodied as shown in FIG. 1 in
an illustrative TDM color mixing embodiment. In similar fashion:
independent control signals for the pluralities of red, green, and blue
LEDs of the color mixing light source W are indicated in FIG. 11 as R(W),
G(W), and B(W) respectively; independent control signals for the
pluralities of red, green, and blue LEDs of the color mixing light source
X are indicated in FIG. 11 as R(X), G(X), and B(X) respectively;
independent control signals for the pluralities of red, green, and blue
LEDs of the color mixing light source Y are indicated in FIG. 11 as R(Y),
G(Y), and B(Y) respectively; and independent control signals for the
pluralities of red, green, and blue LEDs of the color mixing light source
Z are indicated in FIG. 11 as R(Z), G(Z), and B(Z) respectively.

[0079] The controller 200 further receives input signals via the connector
assembly 182, 184, which in the embodiment illustrated in FIG. 11 include
at least: a "Tail signal" corresponding to the taillight indicator signal
generated by the automobile 150 when, for example, the driver turns on
the vehicle headlights; a "Brake signal" corresponding to the brake
indicator signal generated by the automobile 150 whenever the driver
depresses the brake pedal or otherwise activates the vehicle brakes; a
"Turn signal" corresponding to the turn signal indicator signal generated
by the automobile 150 when the driver activates the turn signal control
lever or otherwise activates the turn signal; and a "Backup signal"
corresponding to the backup indicator signal generated by the automobile
150 whenever the vehicle transmission is placed into reverse. It is to be
understood that the "Turn signal" can be a left turn signal indicator
that is wired into the left taillight assembly 170, or can be a right
turn signal indicator that is wired into the left taillight assembly 172.
The "Tail signal", "Brake signal", "Turn signal", and "Backup" signal
inputs are consonant with existing vehicle signaling standards (as of May
2011) employed in the United States, Europe, and most other geographical
regions.

[0080] The controller 200 is typically housed within or otherwise
supported by the support element 180, or is otherwise a component of the
taillight assembly 170, so that the taillight assembly 170 is a single
installable unit that can be installed on or in the vehicle 150 by
mounting the support element 180 on or to or in a corresponding surface,
recess, receptacle or the like of the vehicle 150 and electrically
connecting the connector assembly 182, 184 with a mating electrical
connector of the vehicle 150. (In some contemplated embodiments, mounting
the support element 180 on the vehicle 150 may simultaneously effectuate
"plugging in" or otherwise connecting the electrical connector assembly
182, 184.) However, it is also contemplated for the controller 200 to be
physically separate from the illumination unit defined by the support
element 180 and the supported plurality of interspersed pluralities of
LEDs of the color mixing light sources V, W, X, Y, Z.

[0081] With reference to FIGS. 1 and 11, the light output by the taillight
assembly 170 responsive to a given input signal is controlled by a
processor 202 and cooperating electronic hardware 204 that embody
controller components such as the R/G/B switch 14 (where one such switch
is provided for each of the color mixing light sources V, W, X, Y, Z)
color controller 16, current controller 70, and optional optical feedback
control components 20, 22. The constant current power source 12 is also
typically embodied as part of the electronic hardware 204, although it is
also contemplated for external constant current power to be provided to
the controller 200. The processor 202 also performs suitable
transformation of the input signal to generate the desired or setpoint
color (Colorset) 60 and the setpoint intensity (Eset) 72 for
each of the color mixing light sources V, W, X, Y, Z. The transformation
performed by the processor 202 is determined by programming of the
processor 202 and by one or more configuration settings that are stored
in an electronic configuration memory 206, which may be, for example: an
electronically erasable programmable read-only-memory (EEPROM); a flash
memory; a field-programmable gate array (FPGA); or so forth. Some
contemplated configuration settings include, for example: a geographical
region configuration setting; a vehicle model configuration setting; a
vehicle trim configuration setting; a "show mode" in which configuration
the processor 202 causes the taillight assembly 170 to emit a flashing
multicolor or other attention-grabbing light pattern (for example,
intended for use when the vehicle is parked, or when being displayed at
the automobile dealership); or so forth. The configuration settings may
be loaded into the memory 206 by various pathways, such as by a wired or
wireless firmware update pathway (for example, a digital input jack such
as a USB port, serial poll, custom port, Bluetooth connection, or so
forth that connects the controller 200 with a computer or other digital
device (not shown) to load or update the configuration parameters. In
some embodiments, one or more configuration settings may be loaded by a
mechanical switch, such as an illustrated geographical region selection
switch 208 disposed on a top of the support element 180. The illustrated
geographical region selection switch 208 has two settings: "U.S." (switch
moved to the left); and "EUR" (i.e., "Europe", switch moved to the
right). Although not illustrated, a three-setting switch or a plurality
of dip switches or the like may be used to accommodate more selectable
geographical regions if desired. In the illustrated embodiment, the
setting of the geographical region selection switch 208 is read by the
processor 202 and suitable settings are loaded into the configuration
memory 206; however, it is also contemplated to omit the configuration
memory 206 and have the processor 202 directly read the geographical
region selection switch 208 (or other mechanical switch) to determine one
or more configuration settings. In other embodiments, the configuration
settings loaded into the memory 206 may be user programmable. By way of
illustrative example, the dealer may optionally load user programmed
settings selected by the vehicle purchaser so that the operation of the
taillight assembly 170 conforms with the purchaser's personal choices (so
that the taillight is a "designer" taillight). As another illustrative
example, the dealer or manufacturer may load specially programmed
settings for vehicles intended for specialized uses such as unmarked
police cars, emergency vehicles, or so forth.

The colors listed in Table 1 are visually perceived colors. The visually
perceived color yellow is suitably generated by color mixing of the
interspersed pluralities of red and green LEDs at approximately equal
intensities. The visually perceived color white is suitably generated by
color mixing of the interspersed pluralities of red, green, and blue
light at approximately equal intensities. The visually perceived color
red is suitably generated by operating the plurality of red LEDs alone,
or by operating the plurality of red LEDs at a high relative intensity
together with one or both of the plurality of green LEDs and/or the
plurality of blue LEDs operated at a relatively low intensity to provide
a red color point that is shifted slightly toward the green or blue. The
term "flashing yellow" indicates the red and green LEDs of the color
mixing light source are cycled on and off at a rate substantially slower
than the human eye response, so that the human eye perceives the flashing
(this "flashing" is to be distinguished from the fast switching rate
employed in PWM, TDM, or other "switching-type" color mixing schemes in
which the fast switching rate is so fast as to be visually imperceptible
so as to generate a time-integrated color mixture). Similarly, the terms
"flashing yellow/low red" and "flashing yellow/high red" indicate slow
(i.e., visually perceived "flashing") between yellow (generated by
operating the pluralities of red and green LEDs) and red (generated, for
example, by operating the plurality of red LEDs alone).

[0083] Table 1 sets forth signal lights for various input signals that
comport generally with existing road regulations in the United States and
Europe as of May 2011. However, the detailed signal requirements may
differ regionally. For example, although most geographical regions use
red signal lighting for taillighting and for brake lighting, the specific
allowable color points within the red spectral region may be different in
different geographical regions. When using an LED signal lamp that does
not employ color mixing, each geographical regional variation requires a
different taillight assembly, and hence a different SKU line. In
contrast, with the taillight assembly of FIGS. 9-11, such geographical
differences can be accommodated in a single SKU line, by making
appropriate configuration setting changes (for example, by installing a
firmware update, or by setting the appropriate setting on a mechanical
configuration switch). A vehicle assembly facility can therefore stock a
single SKU line, and configure the taillight assembly for the intended
destination country at the assembly facility. If the vehicle manufacturer
employs a "just-in-time" delivery system or otherwise needs to
re-allocate the vehicle after manufacture, refitting the vehicle
taillight assemblies for the new geographical region destination entails
merely resetting the taillight assembly configuration settings, for
example by resetting the switch 208 or by loading a firmware update.

[0084] Moreover, the configuration settings can be adjusted to accommodate
incremental changes in governing regulations. For example, if the United
States were to update its road regulations to require a different shade
of red for tail lighting, such a change in governing regulations can be
readily accommodated by changing the configuration settings. Indeed, such
a change could even be made retroactively, by making the appropriate
firmware update on existing vehicle taillight assemblies.

[0085] Still further, the taillight assemblies 170, 172 can readily
implement additional features not readily provided in existing
taillights. For example, due to cost considerations the same red lamp is
sometimes used for both taillighting and brake lighting. As a result, the
brake light is identical with the taillight except for the intensity,
which is higher during braking. However, the taillight assemblies 170,
172 can readily provide a slight change in the shade or hue of the red
color point to provide a further visual indicium of braking. For example,
the "low red" corresponding to tail lighting can be implemented as an
"orangish" red, that is, by a red whose color point is shifted slightly
toward green, by operating the plurality of red LEDs at high relative
intensity together with the plurality of green LEDs operating at low
relative intensity to shift the color point slightly. The brake lighting
then is suitably implemented by operating the red LEDs alone, providing a
more "pure" red color point during braking.

[0086] The ability to adjust operation of the taillight assemblies 170,
172 via the configuration settings can also be useful to differentiate
different trims of the same vehicle model. In the automobile industry, it
is common to market substantially the same vehicle, that is, the same
model of vehicle, in different trims where the higher trims provide
additional enhancements or features at higher cost. For example, the base
trim may have manual windows and door locks and plain decoration, whereas
a higher trim may have automatic windows and door locks and additional
decoration such as decorative side strips or so forth. Using the
taillight assemblies 170, 172, it is straightforward to implement such
trim-based differences at the signal lighting level. For example, in the
United States either flashing red or flashing yellow lighting can be used
for turn indicators. It is contemplated to program the controller 200 via
the configuration settings to use flashing red turn indicators for the
base trim, and to use flashing yellow indicators for higher trims.
Similarly, other trim-based variations in the signal lighting can be
readily implemented.

[0087] The operation of the taillight assemblies 170, 172 as described
with reference to Table 1 is conventional and complies with existing
vehicle signal regulations in the United States as of May 2011. However,
it is contemplated to provide additional signal lighting capability that
may or may not be compliant with existing vehicle signal regulations in
the United States. These additional signal lighting capabilities may be
allowable in other geographical regions, and/or may be allowable in the
United States but not in common use, and/or may be capabilities that
could become allowable in the United States or other geographical regions
at some time in the future due to evolution of applicable legal
regulations. Some contemplated additional signal capabilities that can be
implemented using the taillight assemblies 170, 172 are set forth in
Table 2.

The use of the color mixing light sources V, W, X, Y, Z in the taillight
assemblies 170, 172 makes implementation of such additional capabilities
straightforward. For the panic brake signal, an additional input called
"Panic brake signal" in FIG. 11 is indicated in phantom as provided to
the controller 200, which is indicative of an especially fast and hard
braking event (that is, a "panic braking" event). Similarly, an
"acceleration signal" and a "fast acceleration signal" is indicated in
phantom as provided to the controller 200, which is indicative of
acceleration and faster acceleration, respectively. In some embodiments,
the "acceleration signal" is activated responsive to the throttle (that
is, the "gas pedal") being depressed, while the "faster acceleration
signal" is activated responsive to increased throttle activation.

[0088] With continuing reference to FIGS. 9-11 and with further reference
to FIG. 12, another optional capability that can be readily incorporated
is real-time adjustment of the signal lighting in response to a changing
environmental condition, such as precipitation, humidity, visibility,
altitude, or ambient light. Toward this end, an environmental sensor,
such as a humidity or rain sensor 210 (shown in phantom in FIG. 10) is
integrated into or in operative communication with the controller 200.
The environmental sensor 210 can be integral with or (as shown) separate
from the taillight assembly 170. Based on a signal received by the
controller 200 from the sensor 210, a signal light is adjusted. For
example, based on the sensed humidity or precipitation, a high relative
intensity of the plurality of red LEDs and/or a low relative intensity of
the plurality of green LEDs or plurality of blue LEDs can be adjusted to
adjust the color point of the visually perceived red color. It has been
observed that human visual perception of a "yellowish" red light is
better in poor visibility conditions (such as fog, rain, or other high
humidity conditions) than is human visual perception of a more pure red
light. Accordingly, the controller 200 can include a look-up table or
mathematical function such as that depicted in FIG. 12, which outputs a
more yellowish color point for the red color light as the humidity
increases. As indicated on the right-hand side of FIG. 12, this can be
accomplished by mixing in more green light. In embodiments in which the
color mixing light source includes interspersed pluralities of red and
amber LEDs, but no green or blue LEDs, a similar effect can be achieved
by mixing in more yellow or amber light. Similarly, the preferred color
point for red light may change with altitude (higher altitude typically
correlates with less dense air, which may tend to motivate toward a more
pure red light), ambient light intensity, or so forth. While adjustment
of the color point of the red light is illustrated, it is also
contemplated to adjust the yellow or amber color point of the turn signal
and/or the color temperature or other characteristics of the white backup
signal.

[0089] With reference to FIGS. 13 and 14, other configurations can be used
for the taillight assemblies, and in some such configurations one or more
color mixing light sources may be combined with one or more LED-based or
non-LED-based lamps that are not color mixing light sources. FIG. 13
depicts left and right taillight assemblies 270, 272 which each include
two light sources A, B, of which one or both is a color mixing light
source. FIG. 14 depicts left and right taillight assemblies 370, 372
which each include three light sources J, K, L of which at least one is a
color mixing light source.

[0090] With particular reference to FIG. 13, in some embodiments lamp A is
a color mixing light source, while lamp B is a white lamp that is not a
color mixing light source. The taillight assemblies 270, 272 can provide
full tail/brake/turn/backup signaling capability, for example as set
forth in Table 3.

Lamp B provides only white light to indicate backup, and accordingly can
be embodied by any white light source, including for example: a white
incandescent lamp; a white LED-based lamp; or so forth. Lamp A in various
signaling modes emits red, yellow, or white light, and is suitably
embodied as a color mixing light source. Advantageously, when lamp A
generates light of a white color, the ratio of red, green, and blue
intensities can be tuned based on the configuration settings in order to
closely match the color temperature and other characteristics of the
white lamp B. Alternatively, lamp A can be configured to generate white
light of different characteristics, for example to provide a
complementary white illumination.

[0091] In other embodiments, lamp B is also a color mixing light source.
In such embodiments, the combination of lamps A, B can be used together
to provide signal lighting of larger area, as illustrated in Table 4.

For the signaling modes in which a tail or brake light is illuminated
together with the turn indicator, the operating mode in Table 4 shows
"Flashing high (low) red/yellow" for lamp A and "Flashing yellow/high
(low) red" for lamp B. This produces "out-of-phase" flashing in which
lamp A is red when lamp B is yellow and vice versa. In some geographical
regions, out-of-phase flashing at the rear of the vehicle may not meet
relevant government regulations regarding vehicle signaling lights, but
where it is allowed the out-of-phase flashing is expected to provide
higher visibility. Advantageously, it is straightforward to use.

[0092] Additional features described with reference to the taillight
assemblies 170, 172, such as color point adjustment on a geographical
region basis or on another basis and/or inclusion of real-time adjustment
based on sensor feedback, can also be incorporated into the color mixing
light source or sources A, B.

[0093] With reference to FIG. 14, as yet another example left and right
taillight assemblies 370, 372 each include three color mixing light
sources J, K, L with the color mixing light source J being located
outermost on the vehicle 150 and the color mixing light source L being
located innermost on the vehicle 150. Table 5 provides a suitable set of
operational modes for the various signaling modalities.

[0094] For turn indicators (other than when backup is simultaneously being
signaled), the out-of-phase operation described with reference to FIG. 13
is extended in the embodiment of FIG. 14 to define a "chaser"
arrangement, in which the yellow light moves "outward" starting at the
innermost color mixing light source L and then flashing to the middle
color mixing light source K and finally to the outermost color mixing
light source J.

[0095] In Table 5 panic braking is indicated by a combination of flashing
high intensity red lights and a central flashing red/yellow light. If the
jurisdiction does not permit yellow light output for rearward facing
signal lights, then only flashing high intensity red lights can be
employed. In another contemplated approach, the area of the red light is
changed to indicate hard (i.e., panic) braking. For example, light source
L may be unused (i.e., off) during normal operations (e.g., as a
taillight or brake light, but still used to emit white light during
backup). In this approach, the light source L is suitably operated to
emit red light during panic braking so that the total area of red light
emission is increased to indicate panic braking. In such embodiments, it
may be useful to modify the light source L to be larger than shown in
FIG. 14, so that the increase in area is more pronounced. In such
embodiments the light source L may additionally be used to emit white
light indicating backup.

[0096] With returning reference to FIGS. 9 and 10, it will be observed
that the taillight assemblies 170, 172 have a 180° rotational
symmetry. In other words, taking the left taillight assembly 170 and
rotating it 180° makes the turn indicator arrow point to the
right. As such, a single SKU line can be used for both left and right
taillights 170, 172, with the taillight assembly of FIG. 10 mounted
"upside down" and connected with the right turn indicator signal of the
vehicle 150 to implement the right taillight assembly 172.

[0097] With reference to FIGS. 15 and 16, if the taillight assembly does
not have 180° symmetry, it is conventionally not possible to use
the same SKU line for both left and right taillights. However, by using
color mixing light sources, this difficulty can be overcome if the
physical extent of the taillight assembly has 180° rotational
symmetry. Such an example is shown in FIG. 15, where a left taillight 470
and a right taillight 472 have 180° rotational symmetry respective
to the entire illuminated taillight area, but the functionality of the
light regions does not have this symmetry. The left taillight 470 has a
turn indicator region 480 that is smaller in area than a tail/brake
region 482, while an inner light region 484 serves as the backup light.
The right taillight 472 has a turn indicator region 490 that is smaller
in area than a tail/brake region 492, while an inner light region 494
serves as the backup light. The size asymmetry of light regions 480, 482
and 490, 492 breaks the 180° symmetry at the functional level. As
shown in FIG. 16 and Table 6, however, a single SKU line can embody both
left and right taillights 470, 472 by suitably representing the larger
light region 480, 490 by two color mixing light sources, one of which is
sized the same as the smaller light region 482, 492, and by suitably
mapping the color mixing light sources to the functionality. Thus, the
taillight assembly as shown in FIG. 16 includes color mixing light
sources M, N, P, Q which are used differently when mounted in the left or
right taillight positions, as detailed in Table 6.

As seen in Table 6, the color mixing light source P is red in both the
left and right taillight positions, while the color mixing light source M
is white in both the left and right taillight positions. Accordingly, the
color mixing light sources M, P can optionally be replaced by another
type of light source. For example, the color mixing light sources M, P
can optionally be replaced by incandescent lamps, non-color mixing
LED-based light sources, or so forth. However, the light sources N, Q are
color mixing light sources, and are set to either red or yellow output
depending on whether they are used in the left or right taillight
positions, in accordance with Table 6. The selection of the left or right
position can be made using a "left/right" switch (not shown) similar to
the region switch 208 for the taillight assembly 270. Other ways of
inputting the left/right configuration setting include loading this
information into firmware using a suitable digital input such as a USB
port, or including a strategically placed sensor on the taillight
assembly housing that is activated when the taillight assembly is mounted
on the left-hand side of the vehicle but not when the taillight assembly
is mounted on the right-hand side of the vehicle (or vice-versa).

[0098] The taillight assembly can be constructed with various levels of
modularity. If the taillight assembly including any associated optics is
constructed as a single unit (for example, a single sealed unit to ensure
weatherproof construction), then that unit will typically be designed for
a single vehicle make/model.

[0099] With reference to FIGS. 17 and 18, in other embodiments it is
contemplated to construct the taillight assembly as a combination of
components. FIGS. 17 and 18 show diagrammatic overhead views of the rear
right corner of two different automobile models (that is, the rear
"right" corner respective to the driver's vantage point). In these views,
the rear of the vehicle is denoted "rear" and the right side of the
vehicle is denoted "right-side". The vehicle of FIG. 17 includes a
taillight assembly 500 comprising a color mixing light source array
module 502 and an optical module 504. The illustrative color mixing light
source array module 502 includes five light source elements 510, 512,
514, 516, 518. In the taillight assembly 500 of the vehicle of FIG. 17,
these five light source elements are coupled into five respective optical
paths 520, 522, 524, 526, 528 shaped to define five color-mixing signal
lights facing generally rearward. The optical paths 520, 522, 524, 526,
528 include suitable refractive, reflective, dispersive, scattering, or
other passive optical elements such as light guides, lenses, mirrors, or
so forth, and are cosmetically shaped to blend in with and contribute to
the aesthetics of the rear right corner of the vehicle. Thus, five color
mixing light sources are defined: a color mixing light source 510, 520; a
color mixing light source 512, 522; a color mixing light source 514, 524;
a color mixing light source 516, 526; and a color mixing light source
518, 528. These five color mixing light sources are customized to the
make/model of the vehicle of FIG. 17 based on the shaping or other
configuration of the optical module 504. In similar fashion, FIG. 18
shows a vehicle of another make/model, which has a taillight assembly 600
comprising the same color mixing light source array module 502 shown in
FIG. 17, but optically coupled with a different optical module 604
comprising only three optical paths 620, 622, 624. In this arrangement,
the two color mixing light source elements 510, 512 are coupled with the
optical path 620 to form a first color mixing light source. The two color
mixing light source elements 514, 516 are coupled with the optical path
622 to form a second color mixing light source. The single color mixing
light source element 518 is coupled with the optical path 624 to form a
third color mixing light source. The color mixing light sources of the
taillight assemblies 500, 600 of FIGS. 17 and 18 are used as already
described. For example, in the embodiment of FIG. 18 the color mixing
light source 510, 512, 620 can function equivalently to the light source
J of the embodiment of FIG. 14, the color mixing light source 514, 516,
622 can function equivalently to the light source K of the embodiment of
FIG. 14, and the color mixing light source 518, 624 can function
equivalently to the light source L of the embodiment of FIG. 14, and the
taillight assembly 600 is then suitably operated in accordance with Table
5 to implement various signaling functionality. Advantageously, in this
modular configuration the color mixing light source array module 502 can
be marketed under a single SKU that is installable in a variety of
different vehicle makes/models. In such embodiments, the color mixing
light source array module 502 includes the controller 200 (see FIG. 11)
integrally included in or with the module 502 as a unitary assembly to
independently and selectively drive the light source elements 510, 512,
514, 516, 518 to generate light of selected visually perceived colors.
The electronic configuration memory 206 of the controller 200 is suitably
programmed (e.g., manually or by an automatic mechanism) to comport with
the make/model of vehicle into which the module 502 is installed.
Moreover, it is contemplated for the color mixing light source array
module 502 to be usable for other vehicle lighting purposes in
conjunction with suitable optics modules, such as for vehicle interior
lighting for convenience, safety, and/or ambience. In such embodiments,
the color mixing light source array module 502 is preferably manufactured
to standards (respective to parameters such as rated operating
temperature range, rated water resistance, input voltage, color mixing
controller configuration, and so forth) so as to be suitable for general
vehicular use including but not necessarily limited to taillight
applications.

[0100] The foregoing disclosure has utilized taillight assemblies as
illustrative signal light assemblies. However, the disclosed vehicle
signal light assemblies can also be used for other types of signal
lights, such as the center taillight assembly 174, or for side signal
lights, or for front turn indicator/parking light assemblies, or so
forth. In some contemplated embodiments, the disclosed color mixing
lighting module can also be used for implementing non-signaling lighting
functions, like auxiliary lighting inside the car, dashboard lighting,
ambient lighting, or so forth.

[0101] The preferred embodiments have been illustrated and described.
Obviously, modifications and alterations will occur to others upon
reading and understanding the preceding detailed description. It is
intended that the invention be construed as including all such
modifications and alterations insofar as they come within the scope of
the appended claims or the equivalents thereof.